What is the main goal of unit testing?

Unit testing focuses on validating individual components or modules of a software application to ensure they behave as expected. The primary goal is to verify that each unit of the software performs its intended functionality correctly in isolation. By testing components individually, developers can identify and address defects early in the development process, leading to more reliable software.

This approach allows for easier debugging and maintenance, as problems can be traced back to specific units rather than emerging from interactions among multiple components. It also encourages better coding practices and design, as developers are motivated to write clear, modular, and testable code.

The other options do not align with the primary goal of unit testing. Testing the entire software system at once refers to system or integration testing, while documenting code changes and generating user documentation relate to different aspects of software development, focusing on maintaining records and aiding end-users, respectively.